Centerless grinding



0a. 29;, 1929. I CASTER 1,73%,3

' CENTERLESS GRINDING Filed seist. as. 1926 a, a! l p I l Zia/we Patented Oct. 29, 1929 UNITEDH'S'TATES PATENT oi-"F ea;

Joan E. OABTEB, or momma-0111c, Assrenon To run cmcrmu'rr omnibus,

INCORPORATED, OF CINCINNATI, OHIO, A. CORPORATION OF OHIO crmrmnss Gamma Application filed September as, 1926. serial No. 137,207. i

This invention relates to improvements in centerless inding and has particular reference to ti e mechanism for controlling the feed and discharge of articles to be operated 'upon by the grinder.

One of the objects of the present invention is the provision of an improved mechanism particularly adapted for use in the production of spherical articles such as balls for ball bearings, which will automatically supplywork ieces to the grinding throat prior to the grinding operation and will cause their auto: matic discharge after the grinding has been completed.

A further object of the invention is the provision of novel and improved step by step ad- 'vancing of work pieces tooperative position within the throat of a centerless grinder.

Other objects and advantages of the present invention should be readily apparent by reference to the following specification taken in connection with the appended claims and it will be understood that I-may make any modifications in the specific structural details herein disclosed within the scope of the appended claims without departing from or exceding the spirit of the invention.

Figure 1 is an elevation of a centerless grinder embodying these improvements.

Figure 2 is an enlarged fragmentary vertical sectional view illustrating the release of a work piece.

Figure 3 is a similar'view illustrating a work piece within the grinding throat and the remaining series restrained.

Figure 4 is a fragmentary view illustratingi the discharge movement of a work piece, an a Figure 5 is a fragmentary plan view of the grinding throat including the work rest, and adjacent portions of the grinding and regulating wheels, with the work in position therebetween.

In the drawings the letter A designates the base of a conventional form of centerless grinder supporting a grinding'wheel B and nism' contained within the gear case G'and f driven from motor H. This mechanism in Q 1 cludes a cam and toggle device such as illus I trated' in Figure 6 of my Patent 1,665,084 for example and therefore not here specifically illustrated. It is to be understood either this 1 mechanism, the handle E or other suitable device may be employed to impart the necessary in and out movement to the re lating wheel to vary the width of grinding't roat as formed by the wheels B and G. 1

By reference particularly to Figure 5 it will be noted the grinding wheel is formed with a series of grooves 10 to receive the work pieces 11 which are fed into the grinding throat as through the series of tubes 12, there being a tube for each groove in the grinding wheel. Disposed within the throat between wheels B and G isa work rest blade I having an inclined upper face 13 on which a work piece 11 rests during grinding and having an inclined discharge portion 14 down which the work piece will roll for discharge when the-wheel C is withdrawn as is particularly illustrated in' Figure 4. i a I To control the movement of the work pieces downward, in the several tubes, use is made of a trigger 15 pivoted to the tube as at 16 and adapted to be projected inwardly through the slot 17 as by action of the spring 18. The inner projected end serves to engage the lowermost work piece and normally-retain it in raised position. When desired to release the work piece, so that it may move downward to the work rest, use is made of the bracket19-on the regulating wheel slide having a finger 20 with a trip lug 21 adapted V to engage the upper end of the dog and swing the dog into position clearing the interior of the tube as shown in Figure 3. Prior, however, to the movement of the finger into this position its bevelled or sharpened end 20'will have been projected through slot 17 into the tube to raise the column of work be held up so that but a single ball can drop pieces within the tube and hold the parts in down into \the'work rest and the grinding wheel groove.

It will thus be seen that for each stroke of the regulating wheel inward to decrease the size of the rinding throat, a work piece is presented within the throat on the work rest,

the continued inward movement of the re ulating wheel pressing the work piece, in t is instance a ballixintoone of the grooves of I roll down by gravity off the work rest into a suitable receptacle. In this withdrawing movement the lowermost work piece previous-' ly supported by finger 20 as shown In Figure 3, can then drop down until limited by the trigger 15 and is in position to be fed to the throat as the regulating wheel moves back inv ward.

' aration of the grinding and regulating wheels It will be understood that the mechanism just described is suitable for yarious shapes of articles according to the configuration of the grinding wheel groove and the type of trough or tube used to guide the work piece.

, In the present instance, however, the mechanism has been particularly illustrated as intended for the use in grinding of spheres. When so employed the regulating wheel is preferably set at a slight angle to the horizontal axis, for example about 5 degrees, so that an operative point on the surface of the regulating wheel as the latter is rotated will move in a path diagonally across the groove of the grinding wheel. This is for the purpose of so controlling the rotation of the work that it will not only move about an axis parallel with the work rest as is the case on grinding cylinder rolls for example on a centerless grinding machine, but will also have a diagonal twisting or spinnin motion, so that all portions of the surface 0 the article will be equally presented to the formed face of the grinding wheel. This enables the grinding wheel to remove the desired amount of stock and form a truly spherical surface on each individual work piece. It will be understood the diameter of sphere produced is dependent on the two factors of the shape of the groove in the grinding wheel and the minimum sepas the regulating wheel moves inward. A machine constructed as here shown can produce balls for ball bearings accurate within a few tenths of a thousandth or less as a commercial proposition. Due to the automatic feeding and discharge of the work piece as the regulating wheel is either manually or automatinumber of balls to be simultaneously ground the regulating wheel.

I claim r 1. chanism of the character described mcludmg a bed or support, a workrest rising therefrom, a inding wheel disposed at one s1de of the work rest having a grooved face, a regulating wheel on the opposite side of the work rest, means for varying the distance between said wheels to vary the width of gr nding throat provided thereby, a chute for dischar 'ng a work piece into the grinding throat etween the wheels in alignment with the groove of the grinding wheel, means for normally holding a plurality of work p eces upward in the chute and means associated with the regulating wheel for releas- 1ng individual work pieces from the chute into the grinding throat on each narrowing of the width of said throat.

2. A machine for centerless grinding of spherical articles including a grinding wheel having a work receiving groove formed therem, a regulatin wheel opposing the grinding wheel, means or imparting a relative movement to one of said wheels to vary the width of throat therebetween, a work rest projecting within the grinding throat, a discharge chute having a discharge portion aligned with the groove of the grinding wheel and or produced for each in and out movement of adapted to eject a work piece onto the work rest and within the groove of the grinding wheel, a trigger member for holding work pieces in raised position in the chute, and a release device for said trigger operable'onrelative movement of the wheels, decreasing the Width of the grinding throat.

3. A machine for centerless grinding of spherical articles including a grinding wheel having a work receiving groove formed therein, a regulating wheel opposing the grinding wheel, means for imparting a relative movement to one ofsaid wheels to vary the width of throat therebetween, a work rest projecting within the grinding throat, a discharge chute having a discharge portion aligned with the groove of the grinding wheel and adapted to eject a work piece onto the work rest and within the groove of the grinding wheel, a trigger member for holding work pieces in raised position in the chute, a release device for said trigger operable on relative movement of the wheels, decreasing the width of the grinding throat, and separate means for limiting the movement of work pieces in the chute as the trigger is released.

4. A ball grinding machine of the character described including a grooved grinding wheel and an opposed ungrooved regulating wheel movable toward and from the grinding wheel, a work rest disposed in the throat be-' tween said wheels, a tubular work chute projecting into the throat and adapted to discharge work pieces into the grinding throat,

work detaining finger associated with the release mechanism and projectable into the chute as the triggeris released, said finger when projected within the tube engaging .the work pieces therein to limit the downward movement of all work pieces except the lowermost trigger controlled work piece.

5. A machine of the character described including a work rest and an opposed work feeding device, a grinding wheel disposed at one side of the work'rest for operating on an individual work piece supported thereby, a regulating wheel disposed at the opposite sideof the work .rest in opposition to the grinding wheel for controlling the movement thereof, means for imparting an in and out movement to the regulating wheel relative the grinding wheel to vary the throat to permit of discharge of a completed work piece, a work retaining member carriedby the feeding device for limiting downward movement of work pieces therein, and a work detent movable with the regulating wheel for engagement with work pieces in the work feeding device, said member having a depending lug engageable with the work retaining device on the feeding member subsequent to the engagement of the work supporting device with the work on inward movement of theregula'ting wheel, whereby said lug temporarily releases the work retaining member to permit of discharge of a work piece into the grindin throat between grinding and regulating w eels.

In testimony whereof I afiix my signature.

JOHN E. (EASTER. 

